[crypto] Add scrypt key derivation to SymmetricKey

Add a method for key derivation using the scrypt algorithm to
crypto::SymmetricKey.

Rename the pre-existing method for key derivation (which uses PBKDF2) to
clearly disambiguate between the two.

TBRing because all the changes to files not under crypto/ are a trivial
library method name change.

[email protected],[email protected],[email protected],[email protected],[email protected]

Bug: 875931
Change-Id: Iaa0b2bb0fc3ae2481733072363718cffd8811b97
Reviewed-on: https://chromium-review.googlesource.com/1181881
Commit-Queue: David Davidović <[email protected]>
Reviewed-by: David Benjamin <[email protected]>
Reviewed-by: vitaliii <[email protected]>
Cr-Commit-Position: refs/heads/master@{#586247}
16 files changed